The present invention concerns a keyboard support for orienting a keyboard such as a computer keyboard with respect to a workstation surface.
The personal computer revolution has placed personal computers and computer terminals on corporate and home desktops throughout the world. Almost all such computers and terminals allow data entry through an alphanumeric keyboard. Often such a keyboard rests on a level desktop surface which is the same as the surface that supports the computer.
Especially when the user must work at the computer for long periods of time, it is important to be able to adjust the position and/or orientation of the keyboard. Built in tabs that form an integral part of the keyboard allow a limited amount of tilt adjustment. To allow more flexibility, however, the keyboard needs its own support.
Different types of keyboard supports are sold by Workrite Ergonomics Accessories Inc., assignee of the present invention. One such keyboard support is movably supported by a track that allows the keyboard to be retracted out from under a user""s desk and then stored beneath the desk when the keyboard is not in use. This keyboard support also allows the user to adjust both the angle and the height of the keyboard in relation to its user. The tilt angles of the keyboard can be adjusted through a continuously variable angle of a total of 25 degrees from a negative tilt (front of keyboard elevated with respect to its back) of 15 degrees to a positive tilt (front of keyboard lower than its back) of 10 degrees. This commercially available keyboard is sold by Workrite under the model designation numbers 170, 171, 173, and 175.
Waterloo Furniture Components presently sells a support mechanism that includes a moveable linkage that couples a keyboard support to a desk. The keyboard support rids in a track support on progressive ball bearing slides that are oriented vertically, such that the ball bearings are disposed within planes generally perpendicular to the desk. A tab that extends from the track support housing is pressed by the user to retract and store the keyboard support. The height of the keyboard support is adjusted by rotating the keyboard support up and moving the keyboard support to the desired height and then releasing the keyboard support. The height of the keyboard support is maintained by a braking system made up of two wedge shaped blocks and two bolt holding the blocks within an inclined slot. The Waterloo linkage also includes a mechanism that allows a tilt angle to be varied over a range of about 6 degrees by loosening and then re-tightening a self locking nut. When the locking unit is loosened, a pin can be repositioned within a limited extent slot in a member that forms part of the linkage. This adjustment is made when the keyboard support is being fabricated and is not adjustable by the keyboard user.
One exemplary embodiment of the present invention concerns a keyboard support that allows a keyboard (typically a computer keyboard) to be moved and reoriented with respect to a workstation.
A keyboard supporting member has a generally planar keyboard support surface whose orientation is adjustable. A second, workstation engaging member allows the user to move the keyboard back and forth with respect to the workstation. The movement of the keyboard within the workstation engaging member may be accomplished on nylon slides or other suitable bearings. In an exemplary embodiment of the invention, progressive ball bearing slides oriented horizontally such that the ball bearings are disposed in a plane generally parallel to the workstation are located in the workstation engaging member to allow the user to move the keyboard to a storage position and then move the keyboard to an in use position. This horizontal orientation of the ball bearing slides provides a workstation engaging member having a lower profile than prior art devices. A latch mechanism prevents movement of the keyboard back to the storage position after the keyboard in extended to the in use position unless a lever is pressed. A linkage interconnects the two members for adjusting a relative position of the keyboard supporting member with respect to the workstation engaging member thereby allowing the keyboard position and orientation to be controlled by the user.
The linkage includes a bracket having one end rotatably connected to the workstation engaging member. The bracket extends away from the workstation engaging member at an angle that controls the height of the keyboard in relation to the work surface. The bracket defines a pair of arcuate slots at one end spaced from the end that is connected to the workstation engaging member. The keyboard engaging member defines a pair of fingers each having an arcuate slot located at either side of the planar support surface. A connector passes through the arcuate slots of the bracket, the arcuate slots of the keyboard engaging member, a preload spring, and two wedge shaped pressure applying blocks. The pressure applying blocks exert an inward force on the fingers of the keyboard engaging member which in turn are frictionally engaged with the bracket. The preload spring maintains engagement between the blocks and the arcuate slots. As the force from the pressure applying blocks increases so does the friction force between the bracket and keyboard engaging member, tending to prevent relative motion therebetween. The connector is used for increasing and decreasing a frictional engagement between the pressure applying blocks, the bracket and the keyboard engaging member. As the frictional engagement is increased or decreased by the connector, the wedge shaped pressure applying blocks are urged along an incline in the fingers of the keyboard engaging member and the user is able to adjust an orientation between the keyboard engaging member and the workstation over a continuous range of values. As a example of the exemplary embodiment, tilt angles over a range of 25 degrees can be chosen.
The keyboard engaging member may be manually rotated in a direction which releases the frictional engagement between the pressure applying blocks and the keyboard engaging member""s inclined finger segments allowing free movement of the bracket relative to the workstation engaging member and the user may adjust the height of the keyboard engaging member relative to the workstation. When the bracket is released, the pressure applying blocks move back their original position prior to the manual rotation of the bracket thereby preserving the user""s preferred orientation.